The present invention relates to improvement of a writing implement such as a ball point pen or a felt-tip pen having a pen point serving as a writing point, the improvement being made to a free-ink type collector type writing implement comprising an ink tank for directly storing an ink, a collector which is a vane type regulating member with a plurality of vanes utilizing a capillary phenomenon, for regulating the interior pressure and means for guiding the ink from the ink tank to the pen point.
In conventionally known oil-based ball point pens, for the purpose of decreasing the incidences of forward leaking which is a leakage of an ink from a pen point and back leaking which would occur in the condition that the ball point pen is turned upside down and cause staining of clothes or disable writing, an ink having a high viscosity ranging from about 3,000 to 10,000 mPa S is generally used and the capillary force is increased by making the ink tank thinner so as to prevent the ink from moving, thereby preventing occurrence of the above-mentioned leakage, however, with these measures, the problems of heavy writing sensation, blobbing, unevenness of drawing lines, light density and the like arise.
Furthermore, a so-called reservoir type pen in which a reservoir of a fiber bunch is immersed with an ink having a low viscosity of several mPa S, thereby allowing the ink to be guided to the pen point via an ink guiding feed, however this type of pen also involves the problems that consumption of the ink cannot be recognized, and that though an intense drawing line is obtained in the initial stage because the flow amount of the ink is large, the intensity of the drawing line gradually decreases because the flow amount of the ink gradually decreases due to repeated writing. Conduction of the ink from the reservoir can be improved by making a setting to weaken the capillary force of the reservoir, however, this measure also involves the problems with regard to blowing out of the ink that the incidence of blowing-out, the situation that the ink leaks from the reservoir in response to a shock of dropping to stain cloths is increased, and on the other hand, when the capillary force of the reservoir is increased, the flow amount of the ink significantly drops as the writing is repeated, so that the intensity of the drawing line becomes significantly low in the latter stage of lifetime even though the ink remains sufficiently.
For the purpose of solving the above-mentioned problems associated with the oil-based ball point pen and the reservoir type writing implement, a so-called collector type ink direct-storage type writing implement (hereinafter, referred to as xe2x80x9ccollector type writing implementxe2x80x9d) is known in which a mechanism used in a fountain pen is applied by disposing an ink tank for directly storing the ink in a rearward position, and regulating the air replacement interior pressure at the time of writing by a collector having a plurality of vane-type grooves. The collector type writing implement has an advantage that the flow amount of the ink is as large as or larger than that in the initial stage of the reservoir type writing implement, making it possible to write with an intense drawing line until the final writing without gradual decrease in the flow amount of the ink even if pen pressure is not applied, however, since it is necessary to make the ink storage amount larger than that of the oil-based ball point pen, the diameter of the ink tank is made large and generally about 1 to 3 cc of ink is stored.
In the conventional collector type writing implement, when the atmospheric pressure of the outside air is changed, the internal pressure is regulated by movement of the ink into the collector, thereby preventing the ink from leaking from the tip of the pen point. In order to prevent volatilization of the ink, it is general to provide a cap which seals the airhole and the pen point concurrently utilizing an undercut, however this measure has a certain problem that as a result of change in the internal pressure of the cap due to attachment/removal of the cap, the ink gradually fills the collector and finally flows out of the collector via the air hole when exceeding a limit of retaining capability, which phenomenon is known as a pumping phenomenon.
In addition, the above mechanism has a problem that as a result of repeated cycles of heating and cooling, or repeated cycles of reduced pressure and high pressure in an airplane, high- or, low-atmospheric pressure, difference in altitude and the like, the blowing out phenomenon occurs similarly. The pumping phenomenon can be dealt by, for instance, adopting a movable inner cylinder into the cap. Meanwhile, in order to solve the problem of blowing out caused by repeated cycles of addition and reduction of the pressure in atmospheric pressure, measures to increase the maximum ink retaining capability of the collector (increase the diameter and length) or to decrease the size of the ink tank have been suggested. However, in the case of currently commercially available products which adapt the above measures, the following problems arise: size of a barrel cylinder is increased to cause a problem regarding appearance; the amount of the ink is decreased to shorten the lifetime, which degrades the cost performance; the collector is made excessively longer and thus the height of the ink head toward the pen point becomes large so that forward leakage is likely to occur; and furthermore, when the above problems are addressed by the ink, it is necessary to use an ink which has extremely low wettability, consequently writing performance must be sacrificed.
Furthermore, in the collector type writing implement, it is possible to keep the intense drawing line until the ink is completely consumed, so that there arises a problem that when the ink runs out during use of the pen, the user meets inconvenience such that writing suddenly becomes no longer possible. Meanwhile, request for improvement of the final writing performance is also proposed as follows: to begin with, the state that ink being almost run out from the tank can be visually recognized from the outside; then, from this point of time, the flow amount of the ink gradually decreases and the writing condition in which the drawing line is visible even if the intensity thereof is weak, that is, during almost all of the lifetime of the pen, a desirable writing performance of free-ink condition is assured; and from the point of the time when the ink within the tank runs out, the performance similar to that of the final writing stage of the reservoir type pen can be assured (that is, normal letter writing can be conducted without any problems, though the drawing line is more or less light and ink starving occurs when a fast writing may be performed).
The main object of the present invention is to improve the widely available collector type writing implement, and to concurrently solve the problem that the significant disadvantage of staining clothes of the consumer due to the repeated up and down cycle of the pressure in the airplane, the problem that there is a request of realizing slim appearance for the collector type writing implement which tends to be thick and the problem of final writing performance which suddenly disables writing when the ink runs out, while satisfying the excellent writing performance possessed by the conventional collector type writing implement, by satisfying the request for reliably improving accident preventing properties of the writing implement, such as preventing property of ink leakage caused by up and down of the atmospheric pressure due to attachment/removal of the cap during use, and blowing-out preventing property during storage of long period in stores.
The present invention for solving the above-mentioned problems will be summarized as follows.
The first aspect of the present invention is a so-called collector type writing implement comprising: a pen point having a writing point at a tip end thereof; an ink tank for directly storing ink of relatively low viscosity having a viscosity of 2 to 100 mPa S at the room temperature; a collector which is a vane type regulating member composed of a plurality of vanes utilizing a capillary phenomenon for regulating the inner pressure of the interior; and guiding means such as a feed for guiding the ink from the ink tank to the writing point, wherein a reservoir having an ink holding capability is accommodated in the ink tank being connected with the feed which is the ink guiding means.
The second aspect of the present invention is a writing implement according to the above-mentioned first aspect, wherein the reservoir incorporated in the ink tank has a size such that a maximum ink holding volume s of the reservoir falls within the range of 10% to 60% (preferably, 20% to 50%) of an ink tank internal volume i, and a clearance in which the ink in a free-ink state is movable is provided between a periphery of the reservoir and an inner wall of the ink tank.
The third aspect of the present invention is a writing implement according to the above-mentioned first aspect, wherein a maximum ink holding volume s of the reservoir accommodated in the ink tank, a maximum retaining volume c of the vane of the collector and an ink tank volume i satisfy the relationship of: (ixc3x9770%) greater than (s+c) greater than ixc3x9720%.
The fourth aspect of the present invention is a writing implement according to the above-mentioned second aspect, wherein the maximum ink holding volume s of the reservoir accommodated in the ink tank, a maximum retaining volume c of the vane of the collector and the ink tank volume i satisfy the relationship of: (ixc3x9770%) greater than (s+c) greater than ixc3x9720%.
The fifth aspect of the present invention is a so-called collector type writing implement comprising: a pen point having a writing point at a tip end thereof; an ink tank for directly storing ink of relatively low viscosity having a viscosity of 2 to 100 mPa S at the room temperature; a collector which is a vane type regulating member composed of a plurality of vanes utilizing a capillary phenomenon for regulating the inner pressure of the interior; and guiding means such as a feed for guiding the ink from the ink tank to the writing point, wherein a reservoir having an ink holding capability is accommodated in the ink tank being connected with the feed which is the ink guiding means, and the ink tank is separated into a plurality of, or at least two parts by a ring fixed to the ink tank while the reservoir communicating with all of the parts of the ink tank.
Next, the sixth aspect of the present invention is a writing implement according to the above-mentioned fifth aspect, wherein communication means which enables each of the plurality of ink tank parts to ink communicate and air communicate is provided for either one or combination of the ring, the an inner wall of the ink tank and the reservoir in the form of grooves, holes and projections.
Furthermore, the seventh aspect of the present invention is a writing implement according to the above-mentioned sixth aspect, wherein in the ink tank separated into two parts, an ink tank part located at the front end of the pen point side is larger in volume than the following ink tank part.
The writing implement of the present invention having the above-mentioned configuration is a ball point pen having a holder which holds a ball serving as the writing point at the tip end thereof and a guide hole or a plurality of channel grooves for ensuring a flow path from the ink tank to the ball of the writing point with respect to the pen point having a receiving seat for receiving the writing pressure at the time of writing, and further having a feed in the guide hole serving as means for guiding the ink based on the capillary force from the ink tank to the ball; or a felt-tip pen or markers in which the ink guiding feed itself serves as the pen point. Between the ink tank of a bottomed cup shape and the pen point is provided a collector, and an air communication part, a thin ink groove and a vane type groove part are arranged in plural to allow the ink to enter/exit thereto/therefrom, whereby an air hole for regulating the internal pressure of the pen body is realized.
As the means according to the present invention, a reservoir and the like having an ink holding capability is accommodated in the ink tank being connected with the ink guiding feed. The ink is a low (or intermediate) viscosity ink having a viscosity of 2 to 100 mPa S at the room temperature (around 23 degrees). Also ink based on a pseudo-plastic ink (also referred to as a gel ink) and modified to decrease the viscosity to some extent can be used. In the stationary state, the pseudo-plastic ink has a somewhat higher viscosity and prevents the forward leakage, or the leakage of the ink from the tip end, however, when shear or movement occurs in response to writing operation, the viscosity drops so that smooth writing is enabled. Furthermore, as a solvent which constitutes a base for the ink, in addition to water generally used, various kinds of ink utilizing, for example, organic solvents such as lower alcohol, higher alcohol and xylene, glycols such as ethylene glycol, and esters thereof which can be conventionally used for a collector type writing implement, can be appropriately used.
As for the reservoir used in the present invention, those having a property of holding a certain amount of ink, such as a reservoir used for conventional reservoir type writing implement can be used, and by designing the reservoir to be thin or small so as to keep a sufficient space left between the inner wall of the ink tank and the reservoir when accommodated in the ink tank, the advantageous feature of the free-ink type possessed by the collector type will not be disturbed. In order to reduce the expansion of the air caused by up/down of the pressure in the case where the internal air increases as a result of consumption of the ink, part of the space of the ink tank is occupied by the reservoir which holds the ink, and therefore by reducing the total amount of the air which will expand, it is possible to prevent the blowing out even under up/down of the pressure.
As another means, the volume of the reservoir in the tank is made 10% to 60% (preferably 20% to 50%) of the volume of the ink tank. As still another effective means, the maximum ink holding volume s of the reservoir accommodated in the ink tank, the maximum ink retaining space c which is the total space of the vanes of the collector and the ink tank volume i satisfy the relationship of: (ixc3x9770%) greater than (s+c) greater than ixc3x9720%.
Furthermore, as effective means of the present invention, the ink tank is separated into a plurality of (at least two) parts by a ring fixed to the ink tank, and these parts are communicated so as to allow the reservoir to supply the ink from every part of the ink tank, with the result that it is possible to construct easily by centering the reservoir, and in the case of using in the environment with up/down of pressure under the condition that the space is increased as a result of consumption of the ink, the ink is simply held in the rear half of the ink tank, so that it is possible to prevent a large amount of ink from flowing into the collector.
Furthermore, when the communication means implemented by the grooves, holes or projections for enabling each of the plurality of parts of the tank to ink communicate and air communicate with each other is provided for either one (or combination) of the ring, the inner wall of the ink tank and the reservoir, it is possible to regulate the movability of the ink by the ring without adversely affecting the writing and collector function and the like.
Furthermore, the above effect becomes more significant when in the parts of the ink tank separated into more than two parts, the volume of the ink tank part at the front end on the pen point side is made larger than the volume of the rear ink tank part, and in addition, this means is advantageous in the visibility of the ink in the free-ink state and in ensuring the collector function.
In the present invention, though the safety is improved when the volume of the reservoir is made large, the period in which writing performance as the free-ink type is maintained is reduced, and the period in which the flow amount of the ink rather gradually decreases in accordance with the repeated writing is increased as is the case of the ordinary reservoir type, resulting in reducing difference between them. Furthermore, those designed to have a high retaining efficiency of the collector (that is, the collector is large) need a small space for the reservoir, whereas those designed to have a low retaining efficiency (the collector is small) need a large reservoir.
By appropriately selecting and satisfying the above conditions, it is possible to keep the balance between the contradictory characteristics, that is, improvement of the safety regarding reduction of the air volume of the ink tank, attainment of the writing performance such as flow amount of the ink, appearance and visibility regarding ascertaining of the remaining amount of the ink, and the problem regarding the final writing performance that the writing flow amount gradually decreases in the final stage of writing and the final writing suddenly occurs.
The reservoir used in the present invention may be, as same as the conventional reservoir type, those in which threads of short fiber or long fiber are softly fixed within a casing, a so-called fiber bundle in which threads of long fiber are shaped without using a casing by binder or thermosetting, a so-called plastic feed of which snowcrystal-shaped section is formed by extrusion, a sintered feed formed by fixing small particles by heat or binder while maintaining spaces, and a sponge, as far as they have a certain ink holding capability. The interior capillary force can be appropriately selected by the number of the fibers in the reservoir, however, it is possible to set the capillary force weaker than that of the general reservoir type.
The feed and the plastic feed can be formed of the same materials as those of the reservoir, however, since the capability of feeding out the ink from the ink tank to the pen point is required, the capillary force is set stronger than that of the reservoir.